got the same problem with my c901, whenever i would take pictures and videos using a 4gb m2 card it would not save it self instead a corrupted file would appear and i could not open it, ive tried re flashing the phone and seus as well but still the same problem, i tried other m2 card but still the same problem.. but the funny thing is when im using a lower memory card like 512 its working perfectly fine, is it a bug? could it be fixed? i got the same problem on my c510